Node.js

Agenda

Install
Hello World
Ecosystem
Single threaded
Blocking IO
Servers TCP/HTTP
CTF

Install Node.js

http://nodejs.org

follow wizard

Installed?

$ node --version

v0.10.30

REPL

$ node 

>

$ node 

> var hello = "world";
undefined
>

> hello
'world'
>

Hello world!

var http = require('http'); 

var server = http.createServer(function(req, res){
    res.end("Hello World");
});

server.listen("3000");

Node is

v8 JavaScript runtime
Event driven
Non-blocking standard libraries
Extend with C/C++ addons

Node is not

A framework
A new programming language

What is Node used for?

Web servers

Desktop applications

CLI tools

Websites!

Desktop applications!

CLI tools

Why?

JavaScript everywhere!
Great community (NPM, sponsors)

Sweet Spots!

Real Time IO intensive apps
Speaks JSON
Easy to make APIs

Not so sweet..

Simple crud apps
CPU intensive stuff

Ecosystem

NPM
Bower
Grunt
Yeoman
MongoDB (and other)
Template engines

DEMO 1.5

What's taking so long?!

L1-cache: 3 cycles
L2-cache: 14 cycles
RAM: 250 cycles
Disk: 41 000 000 cycles
Network: 240 000 000 cycles

So: what is non-blocking IO

with these facts in mind?

Sync vs. Async

Node runs on 1 thread only

Almost...

Disk operations and network requests are threaded.

But you can't interfere with those

DEMO 2!

First thing every programmer do...


cout << "Tell me your name: ";
cin >> name;
cout << "Hello " << name << endl;

Let's do that async

process.stdout.write("Tell me your name: ");

process.stdin.on('data', function(name){
    console.log("Hello " + name);
});

WEBSERVERS!

TCP and HTTP

TCP

var tcp = require('net');
var server = tcp.createServer();

server.on('connection', function(connection){
    console.log(connection);
});

server.listen(3000);

Which event are available?

HTTP & DEMO 3

var http = require('http');
var server = http.createServer();

server.on('request', function(req, res){
    res.end("You requested: " + req.headers.host);
});

server.listen(3000);

ORC API

var tcp = require('net');
var stdin = process.openStdin();

var client = tcp.connect('PORT', 'HOST/IP');
client.setEncoding('ENCODING');



stdin.addListener("data", function(d){ ... });



client.on('connect', function(){ ... });

client.write("STRING");

client.on('data', function(data){ ... });

IP: xx.xx.xx.xx
Port: 3000

"JOIN nickname"

Next time?

Connect

Express